Oilfield drilling operations are complex and require an accumulation of as much drilling information as possible about formation stratigraphy, lithology and mineralogy. Such information is acquired by scientists and oilfield engineers through real time and historic well logging programs using both wireline logging and measurements-while-drilling (MWD).
Wireline Logging
In wireline logging, measurements are recorded using wireline logging tools, or sondes, which are lowered into the open wellbore on a wireline. These logging tools typically comprise a sonde section which contains a variety of measurement sensors and a cartridge section, at the upper end, which contains electronics and power supplies. Wireline logging tools can be lowered into a well hole between drill string trips, preproduction following drilling operations and during production.
Specific sonde components per se are rather sophisticated sampling and electronic devices that are often assembled into a combination of three or more tools arranged in series. Some examples known in the art are phasor dual induction spherically focused resistivity sondes, litho-density sondes and gamma ray sondes. Also, there are temperature, acceleration and pressure sondes. Specific sondes vary in length but are usually six feet to thirty feet and operate downhole under a wide range of pressures, temperatures and depths.
Monopole, dipole and quadrupole sonic logging tools are used to measure compression, shear and Stoneley waves which can be used to determine well formation attributes and lithology characteristics. Sondes vary widely in length, diameter and weight. For example, the sondes described above may be fifty feet in length approximately 3.6 inches in diameter and can weight 900 pounds. In other instances production sondes may be smaller, such as 1 and 11/16 inches in diameter, or even smaller, for some applications to pass borehole restrictions related to equipment for oil and gas production control (safety valves, production packers, downhole flow control and monitoring equipment).
The above logging tools can use a variety of specialty sondes such as an azimuthal resistivity imager for quantitative evaluation of laminated forms, fracture formations, formation dips and borehole profiles.
In a typical wireline logging operation a logging tool is assembled and tested by an engineer in the oilfield, delivered to a drilling derrick and lowered to the bottom of a well on a wireline. The wireline tool is then drawn up the borehole and sampling is performed, typically every 15 centimeters or so, as the tool is raised. In general, well logging has either a scientific or technical program associated with the logging run and uses acoustic, nuclear and/or electrical measurement techniques to record data and/or information that permits scientists to access information such as resistivity, velocity, density, porosity, gamma ray, geochemistry, imaging, vertical seismic profile, temperature and pressure measurements and borehole drilling parameters. Some of this information is transmitted to the surface via an electrical wire or fiber optic cable on a real time basis.
Measurements-while-Drilling
In addition to wireline logging, similar downhole measurements can be obtained using measurements-while-drilling (MWD) tools. These tools are appropriate under certain conditions. For example, highly deviated wellbores are difficult and time consuming to measure with conventional wireline tools. In these cases, MWD tools typically use less rig time and thus save costs. Evaluation of physical properties such as pressure, temperature and wellbore trajectory in three-dimensional space and other borehole characteristics are typical measurements taken using MWD procedures. MWD is now standard practice in many instances such as drilling offshore directional wells.
MWD tools can deliver data to the surface immediately, (i.e. by digitally encoding data and transmitting it as pressure pluses in the mud system). Alternatively, MWD tools can store the data for later retrieval when connected to an electrical wire or, if the data link fails, when the tool is tripped out of the hole.
MWD tools that measure formation parameters such as resistivity, porosity, sonic velocity, gamma ray, etc. of a formation are sometimes known as logging-while-drilling (LWD) tools. In the present invention, however, the terms MWD and LWD are used interchangeably. These tools are often imbedded within the side walls of a section of drill pipe above a drill bit and transmit a certain amount of information to the surface on a real time basis or at least during bit replacement trips.
Logging Tool Management and Data Transfer.
Prior to performing the exemplary operations discussed above, an oilfield engineer must insure that the proper tools are brought on site. This is can be a significant logistical challenge. The site operator must not only keep track of the types and number of these tools, but also record other parameters relating to these tools. Logging tools are run through diagnostic tests and are calibrated. The results of these operations are recorded. Also, hopefully, the usage history of these tools will be logged. Each tool has a particular “useful life” or “lifetime” whose length depends on the hours and conditions under which the tool has been in service. In order to avoid an unacceptable failure rate or catastrophic failure, the tools must be repaired or retired after they reach a statistically determined useful lifespan.
Logging tools are typically fabricated with high strength steel walled cylinders that are capable of withstanding the high abrasion, high pressure and high temperature working environment that exists within a borehole twenty five thousand feet, or so, beneath the surface of the earth. Consequently the data inside the tools is not easily accessed. Even when the data is sought after the tools are brought to the surface, data inside the tools must be accessed through some sort of communication port drilled through the walls of the cylinder. These ports can be a hole in the cylinder side wall through which a connector is inserted and attached to internal data processing equipment. Data is downloaded with telemetry tools, and surface acquisition systems. Setup and supply of power is needed in order to start the data acquisition. This, in turn requires the connection among the tools and the various other telemetry equipment and power supplies with numerous wires and cables.
This data acquisition requires a significant amount of time and effort. Users of the tool string need to confirm all of the diagnostics and calibration status, before shipping the tools to the well site. This may require a few hours in order to just confirm the status and require an expensive surface acquisition system.
One system known in the past that has been designed to facilitate logging tool management and data transfer is disclosed in Smits et al. U.S. Pat. No. 7,230,542, assigned to Schlumberger Technology Corporation, of common assignment as the subject application. The disclosure of this Smits et al. '542 patent, and the prior art cited therein, is incorporated here by reference as though set forth at length. Briefly, however, the '542 patent discloses use of a modular memory cylinder that is plugged into a lateral bore through the side wall of a logging tool. When the tool is raised to the surface the memory module is physically removed from a lateral position within the side wall of the logging tool and a new memory module is put in its place. This newly loaded module is configured with parameters and data related to the tool configuration for the next run.
Although the above noted electronic management and logging tool data retrieval system is a significant advance in the art, it requires the presence of a lateral access port through which the memory modules can be removed. The present invention is yet a her advance which eliminates much of the time and effort required in setting up and collecting well logging and sonde data.
Brief Summary of Aspects of the Invention
Methods and systems disclosed herein allow access to logging tool data, without having to physically connect the tool to a power supply, telemetry equipment, and acquisition system for acquiring the tool data.
Oilfield tools are packaged in thick walled steel pressure tight housings or casings. In some embodiments of the current invention, integrated circuit board devices, placed inside of the metal casings, have silicon chips and antennas to enable storing of data in a buffer and to enable reception of and response to radio-frequency queries. Such devices are referred to here as Radio Frequency Identification Tags (RFTags) and are designed for wireless communication. Although wireless communication is not usually possible through thick walled steel cylinders, an extension antenna enables communication axially through the end of the logging tool so that data may be exchanged to and from RFTags located within the tools by an exterior radio frequency pickup.
RFTags mounted inside of the casing can receive data relating to, for example, temperature, pressure, and other measurements that are made downhole or elsewhere. In this, the present disclosure contemplates transmission of various types of data that are commonly stored and used by tools of the type described herein. Several printed circuit boards (PCBs) are typically present inside the tool casing. RFTags can also be mounted on these PCBs and receive data from the PCB.
These data received from the RFTags are then placed in two-way communication with an antenna portion extending exterior to an end of the cartridge and thus in operative communication with wireless external communication devices.
Typical communication devices include a radio frequency antenna circuit, an RFID reader-writer antenna, a transceiver and a second radio frequency antenna (e.g. BLUETOOTH antenna or wireless LAN antenna).
In one embodiment a smart end cap is mounted at the end of a logging tool component, such as a wireline cartridge. This end cap includes an antenna, a transceiver and a BLUETOOTH or wireless LAN antenna which projects outside of the end of the smart end cap. In response to radio frequency (RF) queries, the data is broadcast by RF and received by external devices for processing. The external devices may be hand held devices that are designed to query and receive data from multiple RFTags.